This invention relates to apparatus for performing underwater therapeutic exercise and particularly to an exercise simulating a stair climbing activity.
It is recognized that therapeutic exercises, e.g., by elderly persons or persons recovering from an illness or accident, are often best performed within a water environment wherein the weight of the exerciser's body is at least partially supported by the water while selected portions of the body are exercised. This allows selective exercising while reducing unwanted stresses.
One exercise which is particularly best performed within a body of water by persons undergoing physical therapy is that of stair climbing. This is because normal stair climbing is so stressful as to be almost impractical as a therapeutic exercise unless the normally high exertions associated with it are greatly reduced.
Stair climbing exercise devices are well known and described, for example, in U.S. Pat. Nos. 3,970,302, 4,726,581, 4,708,338, 3,592,468, and 4,555,108, the subject matter of which are incorporated herein by reference.
In each of the devices of these patents, movable steps are provided which are movable in opposite directions, i.e., one being moved downwardly by the user's foot while the other moves upwardly, and vice versa. Also, each of the devices is provided with means for selectively varying the amount of force required for moving the steps.
The devices described in these patents are not designed for use under water. Proper design of apparatus for use in water, particularly water which is chemically treated, e.g., fluorinated, for hygienic purposes, must overcome several problems. For example, chemically treated water tends to be highly corrosive, thereby excluding the use of many materials and assemblages. Lubricated joints, unless hermetically sealed, are impractical. Also, to avoid the need to remove the apparatus from the pool, the parts of the apparatus should be readily removable and replaceable even if under water.
Thus, for underwater use, an apparatus should be as simple as possible, containing few parts movable with respect to one another, and including a minimum of joints requiring lubrication.
Patents, in the names of applicants herein, plus others, exist showing underwater exercize apparatus. One such patent, U.S. Pat. No. 5,098,085, shows different apparatus simulating rowing, skiing, and skating, using flap means to provide resistance to movable elements moved by the exerciser.
The present invention is directed to a stair climbing apparatus satisfying the aforementioned criteria.